A project under way at 390 Madison Ave. is taking a mid-20th century office building once shrouded in dark glass and turning it into a light-filled, 21st-century office building—only taller.

Sections of floors will be removed, creating the high ceilings that modern tenants desire, and a wraparound terrace will be built on the eighth floor. The square-footage removed from these lower floors will be added to the top—an eight-story addition of pricier office space that also lends a slimmer overall shape to the 1953 structure, currently 24 floors.

“We’ve done it before, but never to this extent,” said Doug Hocking, principal at Kohn Pedersen Fox Associates PC, which worked on the job. “This is a great story of adaptive reuse.”

A hulking building with opaque glass on Manhattan's Madison Avenue is currently wrapped in scaffolding and construction material, signifying to onlookers that something big is happening here. Within the hoarding marking the borders of the site, the 24-storey 380 Madison Avenue is being reincarnated as 390 Madison Avenue in an impressive feat of engineering.